Abstract: The armrest assembly includes a connecting seat, an adjusting rod, a link and an armrest seat. The connecting seat has a connecting rod and a hollow connecting tube with a fixing hole. The adjusting rod has a ring and a bar. The bar is received in the connecting tube and formed with adjusting holes in a row. A fixing block is formed under the adjusting holes and inserted into the fixing hole. The link passes through the connecting tube. Two ends of the link are separately formed with a fixing insert for being inserted into one of the adjusting holes and a pushing button. The armrest seat has a support and an armrest. The support is received in the connecting tube and receives the link. The pushing button projects from a through hole of the support.

Abstract: A fold-down tablet used in a chair is disclosed. The tablet includes a board, a torsion positioning mechanism, a shaft and an armrest. The torsion positioning mechanism is fixed to a side of the board for horizontally rotating and positioning the board. The shaft has a protrudent positioning bar and is fixed to the torsion positioning mechanism for making the board vertically rotatable. The armrest has a shaft hole for rotatably receiving the shaft and a slot communicating with the shaft hole. When the board is turned horizontally, the positioning bar is embedded into the slot to be restricted.

Abstract: A fold-down tablet used in a chair is disclosed. The tablet includes a board, a torsion positioning mechanism, a shaft and an armrest. The torsion positioning mechanism is fixed to a side of the board for horizontally rotating and positioning the board. The shaft has a protrudent positioning bar and is fixed to the torsion positioning mechanism for making the board vertically rotatable. The armrest has a shaft hole for rotatably receiving the shaft and a slot communicating with the shaft hole. When the board is turned horizontally, the positioning bar is embedded into the slot to be restricted.